Does this calculator work for LED, HID, or CMH lights?

Yes — it works for all light types. Efficiency may vary, but wattage is a great starting point for estimating needs.

How accurate is this wattage estimate?

It provides a solid estimate based on grow area and stage. For precision, measure PPFD directly at the canopy.

Just add up the total wattage of all your lights. This tool helps you see if you're within the optimal range.

Grow Light Wattage Calculator

Light. Data. Growth. Smarter cultivation starts here.

Find out how many watts you need based on your grow space and plant stage.

Grow Area Length (ft) [?] Grow Area Width (ft) [?] Plant Stage:

Light Hours per Day [?] Select Your State (optional):Electricity Rate ($/kWh):

Plan, track, and reflect on your grow. The Grow Journal helps you organize tools, notes, schedules, and specs — all in one place.

We estimate watts needed based on area size and plant stage:

Example: a 4×4 grow (16 sq ft) in flower needs ~480–800 watts.

Tool by GrōHaus — helping growers dial in their light, space, and yield.